Drinking Water: Private Wells
About 30 percent of Wisconsin residents get their drinking water from private wells.
What is a private well?
A private well is a way to access groundwater. A well is “private” if it has fewer than 15 connections and serves fewer than 25 people.
A single person or an entity can own a private well. Examples include a small business, mobile home, or school.
Unlike public water systems, protection and maintenance of a private well is largely the responsibility of the well owners.
How do I maintain my well?
A private well needs regular maintenance and inspection. You want to make sure it’s working correctly. Here are ways to protect your well:
- Avoid damaging the well casing. See Learn About Private Water Wells for a diagram of the parts of a well.
- Keep the area around the well clean and safe.
- Make sure the ground slopes away from the well.
- Make sure your well cap is secure and in good condition. It shouldn’t have cracks, holes, or other damage.
- Work with licensed professionals and keep records of all well work and testing. For a list of professionals, see Well and Heat Exchange Contractors.
What substances can be in my private well water?
While most private wells in Wisconsin provide safe drinking water, some may contain substances that can affect our health. Many of these substances do not affect the color, smell, or taste of the water.
The only way to make sure a well is safe for drinking is to test your well regularly using a Wisconsin certified lab. The substances below can be found in private wells in Wisconsin.
Arsenic is a mineral found in soil, bedrock, and water. Exposure to high levels of arsenic can impact our health.
It is important to test for arsenic regularly.
- Test for arsenic at least once every five years.
- Test once a year if arsenic was present in previous tests or you live in Outagamie, Winnebago, or Brown counties.
Our arsenic page has information on how to interpret your test results and what to do if arsenic levels are high.
Bacteria can get into wells when work is done on them, if the well was not built properly, or if there are nearby sources of animal or human waste.
Bacteria testing looks for signs that the water can make people sick.
- Test for bacteria at least once a year.
- Test right away if you notice a change in the color, taste, or smell of the water.
Our bacteria page has information on how to interpret your test results and what to do if bacteria are present.
Pipes, faucets, and other plumbing components in a home can contain lead. There is no safe level of lead exposure. Lead can affect learning, mental health, and increase the risk of diseases later in life.
Testing for your well for lead helps you learn about your water quality.
- Test for lead every five years.
- Also test before the water will be used by someone who is or may become pregnant and by babies.
Our lead in water page has information on how you can protect yourself and your family from this hazard.
Manganese is a common element found in minerals, rocks, and soil. While small amounts of manganese are part of a healthy diet, high levels can affect our health.
Test for manganese if your water is brown or black or stains your faucets, sinks, or laundry.
Our manganese page has information on how to interpret your test results and what to do if manganese levels are high.
Nitrate is a natural molecule found in plants and animals. When it gets in our drinking water, it can affect our health.
It is important to test nitrate regularly.
- Test for nitrate at least once a year.
- Test before the water will be used by someone who is or may become pregnant and babies.
- Test right away if you notice a change in the color, taste, or smell of the water.
Our nitrate page has information on how to interpret your test results and what to do if nitrate levels are high.
Per- and polyfluoroalkyl substances (PFAS) are a group of chemicals that have been used in many products for their heat, grease, and water-resistant properties. Exposure to high levels of some PFAS can affect our health.
if you live near a PFAS contamination site, connect with your local municipality and the DNR to learn potential testing resources. If you do not live near a site of environmental contamination, it is unlikely that PFAS are a problem in your drinking water.
Our PFAS webpage has information on how you can protect yourself and your family this contaminant.
Related topics
Our flooded wells page has information on steps to take if your well has been impacted by flooding.
Our manure page has information on steps to take if your well has been affected by manure contamination.
Our chemical page has information on the other substances that we can be exposed in drinking water, air, and soil.
DNR has a list of certified professionals that can help inspect wells and address issues.
DNR's well compensation grant program page has information about grants to address contamination in private for eligible landowners, renters and business owners.
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